Medtronic Mosaic porcine bioprosthesis: midterm investigational trial results

Late results after mitral valve replacement with Mosaic bioprosthesis in patients aged 65 years or younger

OBJECTIVES

Although in younger patients indications for biological prosthesis implantation in mitral valve replacement remain controversial, recently bioprostheses use increased considerably. We present late results obtained with the Medtronic Mosaic bioprosthesis in patients aged 65 years or younger.

METHODS

Between 2007 and 2017, 67 mitral Mosaic bioprostheses were implanted in patients aged 65 years or younger (58.5 ± 6.4 years). Follow-up extended up to 13 years. Survival, freedom from structural valve degeneration, endocarditis, thromboembolic events and reoperation were considered as main clinical end points evaluated at 1, 5 and 10 years.

RESULTS

The mean follow-up was 4.7 ± 2.8 years. Overall mortality rate was 12%. At 1, 5 and 10 years, survival was 94 ± 3%, 89 ± 4% and 77 ± 9%, respectively. Freedom from structural valve degeneration was 100%, 94 ± 4% and 71 ± 21%. Freedom from endocarditis was 95 ± 3%, 90 ± 6% and 84 ± 8%. Freedom from thromboembolic events was 94 ± 3%, 90 ± 5% and 90 ± 5%. Freedom from reoperation was 94 ± 3%, 87 ± 5% and 65 ± 19%.

CONCLUSIONS

Mosaic bioprosthesis appears a valid mitral valve substitute even when employed in ≤65-year-old patients.

Clinical outcomes and hemodynamic performance of Dafodil™ aortic and mitral pericardial bioprosthesis: 1-year results from Dafodil-1 first-in-human trial

BACKGROUND

Bioprosthesis has been increasingly implanted for the treatment of transvalvular disease across the world. A new Dafodil™ pericardial bioprosthesis (Meril Life Sciences Pvt. Ltd., India) recently approved by Conformité Européenne (CE) is a tri-leaflet, stented, bovine valve. The purpose of Dafodil-1 first-in-human trial was to evaluate clinical safety and performance (including hemodynamic parameters) of the Dafodil pericardial bioprosthesis in patients who underwent aortic or mitral valve replacement.

METHODS

This prospective, multicenter clinical trial enrolled 60 patients (Aortic: 30 patients; Mitral: 30 patients) from seven sites across India. Safety endpoints were early (≤30 days) and late (> 30 days) mortality and valve-related morbidity. The performance endpoints were hemodynamic performance, improvement in NYHA functional class, and change in the quality of life using SF-12v1 health survey.

RESULTS

From July 2017 to July 2018, 60 patients underwent implantation of the Dafodil pericardial bioprosthesis. Post-operatively, NYHA functional class significantly improved in all the patients (Aortic: 90% NYHA class-I and 10% NYHA class-II; Mitral: 96.55% NYHA class-I and 3.45% NYHA class-II; P < 0.001). There was no death in aortic valve replacement patients till 12-month. In mitral valve replacement patients, early mortalities occurred in three patients, and late mortality occurred in one patient; none of these were valve-related. Freedom from all-cause mortality reported was 93.33% at 12-month. Mean aortic pressure gradient decreased from 52.71 ± 24.47 mmHg [with 0.89 ± 0.70 cm² effective orifice area (EOA)] pre-operatively to 14.49 ± 6.58 mmHg (EOA: 1.85 ± 0.27 cm²) at 12-month. Overall, the mitral mean pressure gradient and EOA were 4.41 ± 1.69 mmHg and 2.67 ± 0.48 cm², respectively, at 12-month. Significant improvement (P < 0.05) in the patients' quality of life was reported at all follow-ups.

CONCLUSIONS

The clinical safety and performance of the Dafodil pericardial bioprosthesis were favourable at 12-month. Moreover, a study with a larger patient population and longer follow-up is warranted to further assess the device.

TRIAL REGISTRATION

Dafodil-1 trial has been prospectively registered on 10/07/2017 under Clinical Trial Registry-India (http://www.ctri.nic.in). (Registration number: CTRI/2017/07/009008).

Durability of Mitral Valve Bioprostheses: A Meta-Analysis of Long-Term Follow-up Studies

BACKGROUND

Porcine and pericardial valves exhibited similar freedom from structural valve deterioration after aortic valve replacement. Limited data exist regarding their durability at long-term follow-up in the mitral position.

METHODS

A literature search was performed through online databases. Papers reporting freedom from tissue valve deterioration after mitral valve replacement with a follow-up longer than 5 years were retrieved. Four porcine valves (Carpentier-Edwards [Edwards Lifesciences, Irvine, CA] and Hancock, Hancock II, and Mosaic [Medtronic, Inc, Minneapolis, MN]) and 1 pericardial prosthesis (Carpentier-Edwards) were the objects of the study. The structural valve deterioration (SVD) rate per year was calculated for each type of prosthesis. Kaplan-Meier curves and log-rank test analysis were performed to compare the long-term durability of porcine and pericardial valves.

RESULTS

Forty full-text papers including more than 15,000 patients were considered for the meta-analysis. Porcine valves were generally implanted in younger patients in the first period after their introduction. The mean age of the patients receiving a mitral bioprosthesis increased from 50 to 70 years over the decades. In patients operated after 1980 who had similar mean age at the time of implant, freedom from SVD was higher in the group of porcine valves with Mosaic prosthesis, showing the lowest rate of SVD. Long-term survival was higher for Mosaic porcine and Carpentier pericardial valves.

CONCLUSIONS

In surgical populations that underwent mitral valve replacement after 1980 with new generation tissue valves and similar mean age at the implant time, we found, at long-term follow-up, a higher freedom from SVD in the group of porcine prostheses.

Antithrombotic Strategies After Bioprosthetic Aortic Valve Replacement: A Systematic Review

BACKGROUND

The optimal antithrombotic regimen after bioprosthetic aortic valve replacement (bAVR) is unclear. We conducted a systematic review of various anticoagulation strategies following surgical or transcatheter bAVR (TAVR).

METHODS

We searched Medline, PubMed, Embase, Evidence-Based Medicine Reviews, and gray literature through June 2017 for controlled clinical trials and cohort studies that directly compared different antithrombotic strategies in nonpregnant adults who had undergone bAVR. We assessed risk of bias and graded the strength of the evidence using established methods.

RESULTS

Of 4,554 titles reviewed, 6 clinical trials and 13 cohort studies met inclusion criteria. We found moderate-strength evidence that mortality, thromboembolic events, and bleeding rates are similar between aspirin and warfarin after surgical bAVR. Observational data suggest lower mortality and thromboembolic events with aspirin combined with warfarin compared with aspirin alone after surgical bAVR, but the effect size is small and the combination is associated with a substantial increase in bleeding risk. We found insufficient evidence for all other treatment comparisons in surgical bAVR. In TAVR patients, we found moderate-strength evidence that mortality, stroke, and major cardiac events are similar between dual antiplatelet therapy and aspirin alone, though a nonsignificantly lower rate of bleeding occurred with aspirin alone.

CONCLUSIONS

Treatment with warfarin or aspirin leads to similar outcomes after surgical bAVR. Combining aspirin with warfarin may lead to a small decrease in thromboembolism and mortality, but is accompanied by increased bleeding. For TAVR patients, aspirin is equivalent to dual antiplatelet therapy for reducing thromboembolism and mortality, with a possible decrease in bleeding.

The Mosaic Mitral Valve Bioprosthesis: A Long-Term Clinical and Hemodynamic Follow-Up

We reviewed the cases of 100 patients (mean age, 73 ± 10 yr; 64 men) who had mitral valve replacement with a Medtronic Mosaic porcine bioprosthesis from 1995 through 2011. The mean New York Heart Association (NYHA) class was 3 ± 0.7, and 52 patients were in atrial fibrillation. Prosthetic sizes were chiefly 27 mm (50 patients) and 29 mm (40 patients). Follow-up ended in December 2012 and is 97% complete, with a cumulative duration of 611 patient-years (mean duration, 6 ± 4.6 yr; maximum, 17.7 yr). The early mortality rate was 10% (6% in elective patients); late deaths occurred in 31 patients (5 valve-related). Actuarial survival rates at 5, 10, and 15 years were 74% ± 5%, 50% ± 6%, and 37% ± 8%. The mean NYHA class in survivors was 1.4 ± 0.6 (P <0.0001). Thromboembolic episodes occurred in 4 patients, with an actuarial freedom at 15 years of 91% ± 5%. No cases of endocarditis were observed. Four patients needed reoperation, 2 for structural failure, and 1 each for perivalvular leakage and valve thrombosis. Actuarial freedom from structural failure and from reoperation, respectively, was 93% ± 5% and 91% ± 5% at 15 years. Echocardiographic follow-up in 24 patients with 27-mm prostheses showed a mean gradient of 5 ± 1.7 mmHg and an effective orifice area of 1.57 ± 0.3 cm(2); in 16 patients with 29-mm prostheses, the mean gradient was 4.5 ± 1.9 mmHg, and the effective orifice area, 1.63 ± 0.4 cm(2). During nearly 17 years of follow-up, the Mosaic bioprosthesis has shown good overall clinical and hemodynamic performance after mitral valve replacement.

Randomized trial of carpentier-edwards supraannular prosthesis versus mosaic aortic prosthesis: 6 year results

BACKGROUND

This study prospectively compares the clinical performance of 2 stented porcine aortic bioprostheses: the Carpentier-Edwards supraannular aortic valve (CE-SAV) from Edwards Lifesciences (Irvine, CA) and the Mosaic valve from Medtronic Corp (Minneapolis, MN). We believe it is the only study of this kind.

METHODS

Four hundred three patients undergoing bioprosthetic aortic valve replacement (AVR) between January 2001 and March 2005 were prospectively randomized to receive either the CE-SAV (n = 197) or the Mosaic (n = 206) prosthesis. All patients are being followed annually.

RESULTS

The patients in the 2 groups were comparable with respect to their preoperative demographics, EuroSCORE, and their intraoperative characteristics concerning cardiopulmonary bypass. The mean follow-up period was 6 ± 0.25 years, with a total follow-up of 2,418 patient-years. There have been a total of 64 (32.5%) deaths in the group receiving CE-SAV valves and 85 (41.3%) deaths in the group receiving Mosaic valves. The 5-year survival in the 2 groups was 77.7 % and 73.3%, respectively (p = 0.36). There were no statistically significant differences between the 2 groups in terms of structural valve deterioration (SVD) (p = 0.16), paraprosthetic leak (p = 0.13), thromboembolism (p = 0.25), endocarditis (p = 0.68), and freedom from reoperation at 5 years (p = 0.27). Echocardiographic data suggests a trend for lower valve gradients across the 23-mm CE-SAV prostheses compared with similar-sized Mosaic prostheses.

CONCLUSIONS

There were no statistically significant differences in the clinical performance between CE-SAV and Mosaic aortic prostheses at 6 years after implantation.

Midterm Results After Aortic Valve Replacement With a Stentless Bioprosthesis Aortic Valve

BACKGROUND

It is suggested that a simplified implant model Cryolife-O'Brien (CryoLife International, Kennesaw, GA) offers less satisfactory outcome compared with standard stentless models. This study was conducted to prospectively evaluate the midterm results after aortic valve replacement with the Cryolife-O'Brien stentless bioprosthesis.

METHODS

In 1996, a prospective clinical trial using different stentless valves was initiated. From September 1996 through September 2002, 156 consecutive patients with a mean age of 74.5 years underwent aortic valve replacement with the Cryolife-O'Brien porcine stentless bioprosthesis. The predominant aortic valve lesion was stenosis in 128 and insufficiency in 28 cases. Patients have been followed from 2 to 72 months (mean, 42 months). Echocardiography was performed by one echocardiographer preoperatively, intraoperatively, postoperatively at discharge, 2 to 6 months later, and annually thereafter.

RESULTS

Sixty percent of patients received a valve 25 mm in diameter or larger; 39% had concomittant coronary bypass grafting. The 30-day operative mortality rate was 6.4%. Ten late nonvalve-related deaths have occurred. Severe aortic insufficiency caused by oversizing leads to early reoperation in 3 patients. The peak and mean systolic gradients decreased significantly during the first 12 months after implantation, p < 0.001, and the effective valve areas increased significantly during this time interval p < 0.001. At 5 years, ten patients have moderate aortic insufficiency. The actuarial survival at 5 years was 88 +/- 3%. The rate for freedom from endocarditis was 100% and for freedom from thromboembolic events was 94%.

CONCLUSIONS

Midterm results after aortic valve replacement with the Cryolife-O'Brien stentless bioprosthesis are encouraging. Good hemodynamics have been coupled with low rate of valve-related complications, thus representing a very good alternative to conventional stented bioprostheses.

Prospectively Randomized Evaluation of Stented Xenograft Hemodynamic Function in the Aortic Position

Background— Standard stented aortic xenograft valves have not yet been compared regarding their hemodynamic function using a stratified intraoperative randomization protocol.

Methods and Results— 100 patients were prospectively included after intraoperative metric sizing of the decalcified aortic annulus. They received Mosaic (M) or Perimount (P) aortic valve replacement. Patient age was 73±5 years, 51 were female, and New York Heart Association (NYHA) functional class was 2.8±0.5. The 21-mm annulus group consisted of 5 (M)/7 (P) patients, the 23-mm annulus group of 20 (M)/20 (P), the 25-mm annulus group of 18 (M)/19 (P), and the 27-mm annulus group of 4 (M)/7 (P) patients, respectively. Hemodynamic function was evaluated using transthoracic echocardiography before discharge and at follow-up (438±352 days). Surgery was uncomplicated in all patients. Labeled valve sizes were 0.93 (M) and 1.05 (P) mm smaller than the annulus diameters ( p =NS). In-hospital mortality was 5%, all nonvalve-related. Transvalvular blood flow velocities and transvalvular pressure gradients were significantly lower in the 25 P versus the 25 M group at baseline and in the 23 P and 25 P groups at follow-up. There was a significant regression of left ventricular mass index in all patients at follow-up. However, left ventricular mass regression was more pronounced after P aortic valve replacement.

Conclusion— Labeled sizes of prosthetic heart valves implanted are smaller than the true aortic annulus. Both standard aortic xenografts compared in this prospectively randomized trial provide a sufficient hemodynamic and functional outcome.

Quantification of haemodynamic performance of stented and stentless aortic bioprostheses and potential influence on survival

BACKGROUND

The goal of aortic valve replacement is relief of symptoms, optimisation of haemodynamics, regression of left ventricular mass and advancement of survival. The objective of this review article is to provide the evidence-to-date on the clinical performance of stented and stentless heterograft bioprostheses with regard to haemodynamics, durability and survival.

METHODS

The haemodynamic advantage of aortic valve replacement prostheses is judged on ability to minimise postoperative gradients and to optimise the normalisation of left ventricular mass and function. The most frequent cause of high postoperative gradients occurs when the effective prosthetic valve area is less than that of the normal human valve. The effective orifice area index (EOAI) of >/= 0.85 cm(2)/m(2) is considered optimal to prevent patient-prosthesis mismatch (PPM) at rest and exercise.

RESULTS

The stented bioprostheses contribute to obstructive non-physiological flow patterns whereas stentless bioprostheses provide laminar non-obstructive flow. The stentless bioprostheses have been shown to have larger effective orifice areas and lower gradients. Mismatch is decreased with stentless bioprostheses especially when prosthesis size is </=21 mm. Left ventricular mass (LVM) postoperatively has been shown to relate to baseline LVM index (LVMI) and PPM. The EOAI >0.8 cm(2)/m(2) provides the best long-term regression of LVM. It has been identified that a tendency for PPM in sizes 21 and 23 mm stented bioprostheses did not prevent adequate achievement of appropriate LVMI. Survival at 5 years favoured stentless over stented bioprostheses for patients <70 years, but not in patients >/= _70 years of age. The durability comparison of the stentless bioprostheses must wait until 10-15 years experience is achieved. There is preliminary evidence that uneven shear stress on the leaflet of a regurgitant stentless bioprosthesis can accelerate leaflet tears at the level of the commissures. Dilation of the aortic root and, particularly, the sinotubular junction, can cause progressive stentless valve insufficiency.

CONCLUSIONS

The long-term performance advantages or disadvantages of stentless bioprostheses compared to stented bioprostheses will require at least another 5-7 years of cumulative stentless bioprostheses experience. Surgeons can use an algorithm intraoperatively to prevent patient-prosthesis mismatch while choosing the optimal prosthesis.

Clinical and hemodynamic evaluation of small Perimount aortic valves in patients aged 75 years or older

BACKGROUND

There is the potential for iatrogenic aortic stenosis and poor quality of life when small aortic valve bioprostheses are used in elderly patients. The alternative is enlarging the aortic annulus to accommodate larger size prostheses, increasing operative mortality. It was hoped that bovine pericardial valves would improve hemodynamic performance in the smaller valve sizes.

METHODS

To determine long-term results and in vivo hemodynamic performance of small-size aortic Carpentier-Edwards bovine pericardial valves (Perimount) in elderly patients, we analyzed our follow-up and echocardiographic data from patients 75 years of age or older receiving isolated 19-mm and 21-mm Perimount valves. Ninety-four patients with a mean age of 77 +/- 2.2 years were followed for 12 years. Seventeen patients with 19-mm and 25 patients with 21-mm Perimount valves underwent transthoracic echocardiograms.

RESULTS

Operative mortality was 6.3% (6 of 94). Twelve-year survival was 82.7%. Freedom from thromboembolism was 86.9% at 12 years. Two patients had anticoagulation-related bleeding. Overall New York Heart Association class decreased from 3 +/- 1 to 1.6 +/- 0.7 at the end of follow-up. Hemodynamic performances were satisfactory in both 19-mm and 21-mm Perimount valves, with low peak and mean transvalvular gradients and good effective orifice areas, orifice area indices, and performance indices.

CONCLUSIONS

Perimount aortic valve in the small aortic annulus has yielded excellent long-term results and hemodynamic performances. Perimount is a very satisfactory option in elderly patients. Implantation of a Perimount bioprosthesis avoids enlargement of the small aortic annulus, reducing mortality and morbidity associated with this procedure.

Long-term follow-up of cardiac valve replacement using bioprosthesis in patients 70 years old and older

Good long-term results with the bioprosthetic valves for patients 70 years old and older have been reported. However, because the average lifespan is increasing, we aimed to clarify whether patients older than 70 may still be candidates for valve re-replacement. Seventy-one patients 70 years old and older, who received a total of 81 bioprosthetic valve replacements during 73 procedures between 1988 and 2000, were reviewed. There were 8 hospital and 7 late deaths. Ten-year actual survival after valve replacement was 73.5%, and 82.8% when hospital deaths were excluded. During the follow-up period, 2 patients received mitral valve re-replacement. Ten years of freedom from reoperation were found in 66.7% for all valves and in 50.0% for mitral valves. The average lifespan in Japan is currently 77.64 years for men and 84.62 years for women; therefore, valve degeneration in patients who receive bioprosthesis replacement in their early 70s should be anticipated.

Influence of St. Jude medical valve in patients with aortic stenosis and small aortic annulus on cardiac function and late survival result

This clinical study analyzes our experience of postoperative cardiac function and long-term survival rate in patients with aortic stenosis and small-size St. Jude Medical (SJM) valve. Sixty-eight patients who underwent aortic valve replacement by SJM valve were divided into two groups by preoperative aortic annulus diameter. Group 1 consisted of 44 patients with small aortic annulus and small-size SJM valve (19 mm or 21 mm). In Group 1, small SJM standard valves were implanted in 16 patients, and small SJM Hemodynamic Plus (HP) valves were implanted in 28 patients. Group 2 consisted of 24 patients with large-size SJM standard valve (23 mm or larger). Preoperative left ventricular mass index, left ventricular dimension, the dimension of ascending aorta, and body surface area were significantly smaller in Group 1 than in Group 2. Average age at surgery was older in Group 1 than in Group 2. Effective orifice area index of the SJM valve measured by the manufacturer's data was smaller in Group 1 than in Group 2. Postoperative left ventricular mass indexes of Group 1 (standard valve or HP valve) and Group 2 significantly decreased in comparison with the preoperative mass indexes. Postoperative left ventricular ejection fraction and the peak ejection rate of Group 1 were not different from those of Group 2. The 10 year survival rate of Group 1 was 79%, and the rate of Group 2 was 77%. At 10 years after surgery, freedom from valve-related complication of Group 1 was 80%, and freedom from complication of Group 2 was 81%. Our results demonstrated that small-size SJM valve afforded satisfactory long-term survival rate and valve-related event-free rate for elderly patients with small body surface area and small aortic annulus.